Shermer's Last Law
Any sufficiently advanced extra-terrestrial intelligence is indistinguishable from God.
Any ETI that we might encounter would not be at our level of culture, science, and technology, nor would they be behind us. How far ahead of us would they be? If they were only a little ahead of us on an evolutionary time scale, they would be light years ahead of us technologically, because cultural evolution is much more rapid than biological evolution. God is typically described by Western religions as omniscient and omnipotent. Since we are far from the mark on these traits, how could we possibly distinguish a God who has them absolutely, from an ETI who has them in relatively (to us) copious amounts? Thus, we would be unable to distinguish between absolute and relative omniscience and omnipotence. But if God were only relatively more knowing and powerful than us, then by definition it would be an ETI!
Shermer's Three Principles of Provisional Morality and Evolutionary Ethic
1. The ask-first principle: to find out whether an action is right or wrong, ask first.
2. The happiness principle: it is a higher moral principle to always seek happiness with someone else's happiness in mind, and never seek happiness when it leads to someone else's unhappiness.
3. The liberty principle: it is a higher moral principle to always seek liberty with someone else's liberty in mind, and never seek liberty when it leads to someone else's loss of liberty.
0. The Zeroeth principle: do unto others as you would have them do unto you.
(These principles were derived from a scientific analysis of the evolutionary origins of the moral sentiments and the historical development of evolutionary ethics. The Zeroeth Principle, which precedes the three principles, first evolved hundreds of thousands of years ago but was first codified in writing by the world's great religious leaders and has come down to us as the golden rule. The foundation of the Zeroeth Principle, and the three derivative principles is, in evolutionary theory, reciprocal altruism and the process of reciprocity.)